It’s okay for baby to be asleep while burping. I used to burp my newborn while she’s asleep too. I just let baby rest awhile in the same position before burping. Supporting the neck and go round and round, side to side or just the normal back pat. Occasionally I will lay her over my shoulders. My baby takes a very very long time to burp so sometimes I don’t burp her. When she wants to burp she will fidget then we will pick her up in sitting position and she will self burp 😅 For day time, if she doesn’t burp, I will let her rest 20 -30 mins then lay her in tummy time position (this works everytime for her!) and she will burp herself.